Abrasive rotary tool

ABSTRACT

The disclosure provides abrasive rotary tools with enhanced adhesion of an abrasive layer. Exemplary abrasive rotary tools include a securing element configured to secure an abrasive layer to an abrasive rotary tool. The securing element may be positioned over a portion of the abrasive layer, such as a tab or end, such that repeated forces on the abrasive layer do not decouple the abrasive layer from the rotary tool. In this way, an abrasive rotary tool may maintain a contact surface integrity through repeated use for extended life of the rotary tool.

TECHNICAL FIELD

The invention relates to abrasive rotary tools.

BACKGROUND

Handheld electronics, such as touchscreen smartphones and tablets, ofteninclude a cover glass to provide durability and optical clarity for thedevices. Production of cover glasses may use computer numerical control(CNC) machining for consistency of features in each cover glass andhigh-volume production. The edge finishing of the perimeter of a coverglass and various other features, such as a camera hole, is importantfor strength and cosmetic appearance. Typically, diamond abrasive tools,such as metal bonded diamond tools, are used to machine the coverglasses. These tools may last a relatively long time and may beeffective at high cutting rates. However, the tools may leavemicrocracks in the cover glass that become stress concentration points,which may significantly reduce the strength of the glass. To improve thestrength or appearance of the cover glasses, the edges may be polished.For example, a polishing slurry, such as cerium oxide, is typically usedto polish the glass covers. However, slurry-based polishing may be slowand require multiple polishing steps. Additionally, slurry polishingequipment may be large, expensive, and unique to particular featuresbeing polished. Overall, the slurry polishing systems themselves mayproduce low yields, create rounded corners of the substrate beingabraded, and increase labor requirements.

SUMMARY

The disclosure is generally directed to abrasive rotary tools withenhanced adhesion of an abrasive layer. Exemplary abrasive rotary toolsinclude a securing element configured to secure an abrasive layer to anabrasive rotary tool. The securing element may be positioned over aportion of the abrasive layer, such as a tab or end, such that contactforces on the abrasive layer do not decouple the abrasive layer from therotary tool. In this way, an abrasive rotary tool may maintain a contactsurface integrity through repeated use for extended life of the rotarytool.

In one embodiment, an abrasive rotary tool includes an abrasive assemblyholder, an abrasive layer, and at least one securing element. Theabrasive assembly holder includes a shank and a three-dimensional core.The shank defines an axis of rotation for the rotary tool. Thethree-dimensional core has an exterior surface and is adjacent to theshank. The abrasive layer is adjacent to the exterior surface andincludes a contact surface. The at least one securing element ispositioned over a portion of the abrasive layer and secures the abrasivelayer to the abrasive assembly holder.

In another embodiment, an assembly includes a computer-controlledmachining system that includes a computer controlled rotary tool holderand a substrate platform, a substrate secured to the substrate platform,and an abrasive rotary tool as described above.

In another embodiment, a method for polishing a substrate includesproviding a computer-controlled machining system that includes acomputer controlled rotary tool holder and a substrate platform. Themethod further includes securing an abrasive rotary tool as describedabove to the rotary tool holder of the computer-controlled machiningsystem.

In another embodiment, a method for manufacturing an abrasive rotarytool includes positioning an abrasive layer adjacent to an exteriorsurface of a three-dimensional core of an abrasive assembly holder. Thethree-dimensional core is adjacent to a shank of the abrasive assemblyholder. The abrasive layer includes a contact surface. The shank definesan axis of rotation of the rotary tool. The method further includespositioning at least one securing element over a portion of the abrasivelayer, securing the abrasive layer to the abrasive assembly holder.

The details of one or more embodiments of the disclosure are set forthin the accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

Like symbols in the drawings indicate like elements. Dotted linesindicate optional or functional components, while dashed lines indicatecomponents out of view.

FIG. 1A is a side-view diagram that illustrates an assembly for abradinga substrate.

FIG. 1B is a side view diagram that illustrates an abrasive rotary toolthat includes a securing element securing an abrasive layer to anabrasive assembly holder.

FIG. 2A is a side view diagram that illustrates an abrasive rotary toolthat includes a securing element securing an abrasive layer thatincludes longitudinal tabs.

FIG. 2B is a side view diagram that illustrates an abrasive rotary toolthat includes a securing element securing a wrapped abrasive layer.

FIG. 2C is a side view diagram that illustrates an abrasive rotary toolthat includes a securing element securing an abrasive layer thatincludes radial tabs.

FIG. 3A is a side view diagram that illustrates an abrasive rotary toolthat includes a band securing element securing an abrasive layer.

FIG. 3B is a side view diagram that illustrates an abrasive rotary toolthat includes an O-ring securing element securing an abrasive layer.

FIG. 3C illustrates a side view diagram of an abrasive rotary tool thatincludes a sleeve securing element securing an abrasive layer.

FIG. 3D illustrates a side view diagram of an abrasive rotary tool thatincludes a screw securing element securing an abrasive layer.

FIG. 4A is a top view diagram that illustrates an abrasive layer thatincludes circumferential tabs.

FIG. 4B is a top view diagram that illustrates an abrasive layer thatincludes radial tabs.

FIG. 4C is a top view diagram that illustrates an abrasive layer thatincludes end tabs.

FIG. 5A is a side view cross-sectional diagram that illustrates anabrasive rotary tool that includes a securing element securing anabrasive layer.

FIG. 5B is a side view cross-sectional diagram that illustrates anabrasive rotary tool that includes a securing element securing anabrasive layer.

FIG. 5C is a side view cross-sectional diagram that illustrates anabrasive rotary tool that includes a securing element securing anabrasive layer.

FIG. 5D is a side view cross-sectional diagram that illustrates anabrasive rotary tool that includes a securing element securing anabrasive layer.

FIG. 6 is diagram of a cover glass for an electronic device such as acellular phone, personal music player, or other electronic device.

FIG. 7 is a flowchart that illustrates example techniques formanufacturing an abrasive rotary tool that includes a securing elementsecuring an abrasive layer to an abrasive assembly holder.

FIG. 8 is a flowchart that illustrates example techniques for abrading asubstrate using an abrasive rotary tool.

FIG. 9A is a perspective view diagram of an abrasive rotary toolincludes a sleeve securing element securing an abrasive layer thatincludes circumferential tabs to an abrasive assembly holder.

FIG. 9B is a perspective view diagram of the abrasive rotary tool ofFIG. 9A.

FIG. 9C is a perspective view diagram of an abrasive rotary toolincludes an O-ring securing element securing an abrasive layer thatincludes circumferential tabs to an abrasive assembly holder.

FIG. 9D is a perspective view diagram of the abrasive rotary tool ofFIG. 9C.

FIG. 9E is a perspective view diagram of an abrasive rotary toolincludes an axial securing element securing an abrasive layer thatincludes radial tabs to an abrasive assembly holder.

FIG. 9F is a perspective view diagram of the abrasive rotary tool ofFIG. 9E.

FIG. 9G is a perspective view diagram of an abrasive rotary tool thatincludes two band securing elements securing a wrapped abrasive layerthat includes strips to an abrasive assembly holder.

FIG. 9H is a perspective view diagram of the abrasive rotary tool ofFIG. 9G.

DETAILED DESCRIPTION

The present disclosure describes abrasive rotary tools that feature asecuring element that secures an abrasive layer to the abrasive rotarytool for enhanced adhesion of the abrasive layer.

An abrasive rotary tool includes an abrasive layer coupled to a support.The abrasive layer may be formed as a sheet and cut to a size and shapethat, when applied to an exterior surface of the support, adheres to thesupport and forms the intended contact surface of the rotary tool. Thesupport may have a geometry that includes curved surfaces and/orsurfaces in multiple planes. As such, the abrasive layer may includetabs, strips, or other segmented surfaces that are cut to fit thenon-planar or multi-planar surfaces of the support. During abrading, anabrasive rotary tool may experience forces that cause portions of theabrasive layer to peel, unravel, or otherwise decouple from the support.This problem may be exacerbated by the presence of a compressible layerbehind the abrasive layer which, while allowing the contact surface todeform to a surface of a substrate, may also allow the interface betweenthe abrasive layer and the rotary tool to deform and increase alikelihood of debonding of the abrasive layer from the support.

According to embodiments discussed herein, an abrasive rotary tool mayinclude a securing element configured to secure the abrasive layer tothe rotary tool. The securing element may be positioned over a portionof the abrasive layer, such as a tab or end, such that repeated forceson the abrasive layer are less likely to debond the abrasive layer fromthe rotary tool. In this way, an abrasive rotary tool may maintain acontact surface integrity through repeated use for extended life of therotary tool.

FIG. 1A illustrates an assembly 10, which includes a computer-controlledmachining system 12 and a machining system controller 14. Controller 14is configured to send control signals to machining system 12 for causingmachining system 12 to machine, grind, or abrade a substrate 16 with arotary tool 18, which is mounted within a rotary tool holder 20 ofmachining system 12. In one embodiment, machining system 12 mayrepresent a CNC machine, such as a three, four, or five axis CNCmachine, capable of performing routing, turning, drilling, milling,grinding, abrading, and/or other machining operations, and controller 14may include a CNC controller that issues instructions to rotary toolholder 20 for performing machining, grinding, and/or abrading ofsubstrate 16 with one or more rotary tools 18. Controller 14 may includea general-purpose computer running software, and such a computer maycombine with a CNC controller to provide the functionality of controller14.

Substrate 16 is mounted and secured to substrate platform 22 in a mannerthat facilitates precise machining of substrate 16 by machining system12. Substrate holding fixture 24 secures substrate 16 to substrateplatform 22 and precisely locates substrate 16 relative to machiningsystem 12. Substrate holding fixture 24 may also provide a referencelocation for control programs of machining system 12. While thetechniques disclosed herein may apply to workpieces of any materials,substrate 16 may be a component for an electronic device. In someembodiments, substrate 16 may be a display element, e.g., a transparentdisplay element, of an electronic device, such as a cover glass for anelectronic device or, more particularly, a cover glass of a smartphonetouchscreen. For example, such cover glasses, back covers, or backhousings may include chamfered edges for which a high degree ofplanarity and angularity are desired.

In some embodiments, substrate 16 may include a first major surface 2(e.g. a top of substrate 16), a second major surface 4 (e.g. a bottom ofsubstrate 16), and one or more edge surfaces 6 (e.g. sides of substrate16). The area of edge surface 6 of substrate 16 is typically less thanthe area of the first major surface and/or second major surface ofsubstrate 16. In some embodiments, the ratio of edge surface 6 ofsubstrate 16 to the area of first major surface 2 of substrate 16 and/orthe ratio of edge surface 6 of substrate 16 to the area of second majorsurface 4 of substrate 16 may be greater than 0.00001, greater than0.0001, greater than 0.0005, greater than 0.001, greater than 0.005 oreven greater than 0.01; less than 0.1, less than 0.05 or even less than0.02. In some embodiments, a thickness of edge surface 6 measured normalto first and/or second major surfaces 2, 4, is no greater than 15 mm, nogreater than 4 mm, no greater than 3 mm, no greater than 2 mm or even nogreater than 1 mm. Edge surface 6 intersects first major surface 2 toform a first corner 3 and intersects second major surface 4 to form thesecond corner 5. In some embodiments, edge surface 6 may besubstantially perpendicular to each of major surfaces 2, 4, while inother examples, edge surface 6 may include more than one edge surface,wherein at least one of the more than one edge surfaces is notperpendicular (e.g., a chamfered edge, rounded edge, curved edge orcombination of edge shapes).

In the embodiment of FIG. 1A, rotary tool 18 may be utilized to improvethe surface finish of machined features of substrate 16, such as holesand edge features in a cover glass. In some embodiments, differentrotary tools 18 may be used in series to iteratively improve the surfacefinish of the machined features. For example, assembly 10 may beutilized to provide a coarser grinding step using a first rotary tool18, or a set of rotary tools 18, followed by a finer abrading step usinga second rotary tool 18, or a set of rotary tools 18. In someembodiments, a single rotary tool 18 may include different levels ofabrasion to facilitate an iterative grinding and/or abrading processusing fewer rotary tools 18. Each of these embodiments may reduce thecycle time for finishing and polishing a substrate following themachining of the features of the substrate as compared to otherembodiments in which only a single grinding step is used to shape thesurface followed by polishing substrate features in a separate polishingsystem.

According to embodiments discussed herein, abrasive rotary tool 18 isconfigured to maintain an integrity of an abrasive layer to the toolconstruction while applying a contact pressure against a surface ofsubstrate 16 over a period of time. FIG. 1B is a side view diagramillustrating abrasive rotary tool 18 that includes a securing element 44securing an abrasive layer 40 to an abrasive assembly holder 32.Abrasive rotary tool 18 of FIG. 1B illustrates a general configurationof components of the abrasive rotary tools described herein, such thatother configurations may be used.

Abrasive assembly holder 32 may be configured to transfer a rotationalforce (e.g., a torque) from an abrasive rotary tool holder to anabrasive layer. Abrasive assembly holder 32 includes a shank 34 and athree-dimensional core 36. Shank 34 defines an axis of rotation forrotary tool 18 and is configured to couple to rotary tool holder 20 ofFIG. 1A, such that rotational force from rotary tool holder 20 istransferred to rotary tool 18. Three-dimensional core 36 is adjacent toshank 34. Three-dimensional core 36 may include any volume of materialthat includes substantial x, y, and z components. Three-dimensional core36 includes an exterior surface 38. Exterior surface 38 is configured toprovide a surface for coupling of abrasive layer 40. Core 36 isconfigured to support abrasive layer 40 by providing contact properties,such as shape and hardness, to a contact surface 42 of abrasive layer40. Abrasive layer 40 is adjacent to exterior surface 38 and includes acontact surface 42. Abrasive layer 40 is configured to contact asubstrate at contact surface 42 to remove material from the substrate.

Securing element 44 is positioned over a portion of abrasive layer 40.Securing element 44 is configured to apply a force, such as a claspingor radial compressive force, to a portion of abrasive layer 40 to secureabrasive layer 40 to exterior surface 38. This force resists a debondingforce caused by the abrading action of contact surface 42 on substrate16, thereby securing abrasive layer 40 to abrasive assembly holder 32.In this way, rotary tool 18 may present a contact surface that exhibitsimproved longevity.

Abrasive rotary tools discussed herein may utilize securing elements tosecure a variety of abrasive layers to a variety of abrasive assemblyholders. FIGS. 2A and 2B illustrate two example configurations ofabrasive rotary tools as discussed herein. While securing elements, suchas securing element 44 of FIG. 1B, may be used to secure any abrasivelayer to an abrasive rotary tool, some securing elements discussedherein may be particularly advantageous for securing abrasive layers inwhich one or more edges of the abrasive layer are exposed to tangentialor compressive forces. For example, a rotary force applied to anabrasive rotary tool and transferred to a substrate through an abrasivelayer may cause a leading edge of a portion of the abrasive layer todecouple away from an exterior surface of a core of the abrasive rotarytool. By securing these portions of the abrasive layer to the exteriorsurface with a securing device, the abrasive layer may better resistthis peel force and remain coupled to the exterior surface.

In some examples, at least a portion of the abrasive layer includestabs, such that one or more securing elements may be configured tosecure the tabs to the abrasive rotary tool. FIG. 2A is a side viewdiagram that illustrates an abrasive rotary tool 100 that includes asecuring element 114 securing an abrasive layer 110 that includes tabsto an abrasive assembly holder 102. Abrasive assembly holder 102includes a shank 104 and a three-dimensional core 106. Shank 104 definesan axis of rotation for rotary tool 100. Three-dimensional core 106 isadjacent to shank 104 and includes an exterior surface 108. In theexample of FIG. 2A, three-dimensional core 106 has a cylindrical shape.Abrasive layer 110 is adjacent to exterior surface 108 and includes acontact surface 112. Securing element 114 is positioned over at least aportion of the tabs of abrasive layer 110 to secure the tabs of abrasivelayer 110 to abrasive assembly holder 102. In some examples, thethree-dimensional core includes at least one side-wall adjacent to theexterior surface and the securing element secures the abrasive layer tothe at least one side wall of the three-dimensional core.

During operation, a tangential and/or radial abrading force betweencontact surface 112 and a substrate may cause a leading edge of the tabsof abrasive layer 110 to peel away from exterior surface 108. Securingelement 114 may oppose this peeling action, such that the tabs may beless likely to separate from exterior surface 108 and/or may separatefrom exterior surface 108 at a reduced rate.

In some examples, securing element 114 may only by positioned over aportion of the tabs secured by securing element 114. For example,securing element 114 only contacts the tabs of abrasive layer 110, suchthat securing element 114 does not contact core 106. In some examples,the tabs of abrasive layer 110 are secured to core 106 without overlapof the tabs of abrasive layer 110. For example, overlapping tabs maycause raised sections of an abrasive layer, which may increase a rate ofdebonding of the overlapping tabs. By securing the tabs of abrasivelayer 110 without overlap, abrasive layer 110 may have a reducedvariation in contact pressure from contact surface 112.

In some examples, at least a portion of the abrasive layer includesstrips, such that one or more securing elements may be configured tosecure the strips to the abrasive rotary tool. FIG. 2B illustrates aside view diagram of an abrasive rotary tool 120 that includes asecuring element 134 securing a wrapped abrasive layer 130 that includesstrips to an abrasive assembly holder 122. Abrasive assembly holder 122includes a shank 124 and a three-dimensional core 126. Shank 124 definesan axis of rotation for rotary tool 120. Three-dimensional core 126 isadjacent to shank 124 and includes an exterior surface 128. Abrasivelayer 130 is adjacent to exterior surface 128 and includes a contactsurface 132. Securing element 134 is positioned over strips of abrasivelayer 130. Securing element 134 secures the strips of abrasive layer 130to abrasive assembly holder 122. In some examples, the strips ofabrasive layer 130 are secured to core 126 without overlap of the stripsof abrasive layer 130.

During operation, a tangential and/or radial abrading force betweencontact surface 132 and a substrate may cause a leading edge of thestrips of abrasive layer 130 to peel away from exterior surface 128,which may cause local peeling of the strips and/or loosening of theabrasive layer 130. Securing element 134 may oppose this peeling action,such that the strips may be less likely to separate from exteriorsurface 128 and/or may separate from exterior surface 128 at a reducedrate.

In some examples, at least a portion of the abrasive layer includesradial tabs, such that one or more securing elements may be configuredto secure the radial tabs to the bottom of the abrasive rotary tool.FIG. 2C illustrates a side view diagram of an abrasive rotary tool 140that includes a securing element 154 securing an abrasive layer 150 thatincludes radial tabs to an abrasive assembly holder 142. Abrasiveassembly holder 142 includes a shank 144 and a three-dimensional core146. Shank 144 defines an axis of rotation for rotary tool 140.Three-dimensional core 146 is adjacent to shank 144 and includes anexterior surface 148. Abrasive layer 150 is adjacent to exterior surface148 and includes a contact surface 152. Securing element 154 ispositioned over radial tabs of abrasive layer 150. Securing element 154secures the radial tabs of abrasive layer 150 to the bottom of abrasiveassembly holder 142, such as through a pinching action. In someexamples, the radial tabs of abrasive layer 150 are secured to core 146without overlap of the radial tabs of abrasive layer 150.

During operation, a tangential and/or radial abrading force betweencontact surface 152 and a substrate may cause a leading edge of theradial tabs of abrasive layer 150 to peel away from exterior surface148, which may cause local peeling of the radial tabs of abrasive layer150. Securing element 154 may oppose this peeling action, such that thestrips may be less likely to separate from exterior surface 148 and/ormay separate from exterior surface 148 at a reduced rate.

A variety of securing element designs and materials may be used tosecure an abrasive layer to an abrasive assembly holder, as will befurther discussed below. Because the securing element is configured tosecure the abrasive layer to a three-dimensional core, the design andproperties of the securing element may be selected based on a variety ofdesign and operational factors of and/or regarding the abrasive rotarytool including, but not limited to: properties of the three-dimensionalcore, such as shape, contour, and elasticity; properties of a substratefor which the abrasive rotary tool will be abrading, such as coefficientof friction; properties of the abrasive layer of the abrasive rotarytool; properties of an adhesive between the abrasive layer and theexterior surface of the core, such as peel strength; properties of anassembly operating the abrasive rotary tool, such as an anticipatedrotary force; and the like.

In some examples, the securing element secures the abrasive layer to therotary tool using a radial force toward a rotational axis of the rotarytool. For example, a cylindrical rotary tool may have circumferentialtabs, as shown in FIG. 4A, that extend axially down the rotary tool,such that the securing element may be positioned around the rotary tooland apply a radial force into the rotary tool to secure thecircumferential tabs against the rotary tool. In some examples, thesecuring element is at least one of an O-ring, a band, a wrap, athermally shrinkable sleeve, and a flange.

FIGS. 3A-3C illustrate various band, O-ring, and sleeve securingelements, respectively, that may be used to secure an abrasive layer toan abrasive assembly holder. Each of abrasive rotary tools 200A, 200B,and 200C includes an abrasive assembly holder 202 and an abrasive layer210. Abrasive assembly holder 202 includes a three-dimensional core 206that is adjacent to a shank 204 and includes an exterior surface 208.Abrasive layer 210 is adjacent to exterior surface 208 and includes acontact surface 212. A respective securing element 214A, 214B, and 214Cis positioned over abrasive layer 210 to secure abrasive layer 210.

FIG. 3A illustrates a side view diagram of an abrasive rotary tool 200Athat includes a band securing element 214A securing abrasive layer 210.Band securing element 214A may have a high surface area contactingabrasive layer 210, such that band securing element 214A may remain in asame position during abrading. Band securing element 214A may include,for example, a rubber/elastic band, a heat shrink wrap, orcircumferential layer with a substantially flat surface for contactingabrasive layer 210.

FIG. 3B illustrates a side view diagram of an abrasive rotary tool 200Bthat includes an O-ring securing element 214B securing abrasive layer210. O-ring securing element 214B may have a low roll resistance, suchthat O-ring securing element 214B may be easily positioned onto abrasivelayer 210, such as during manufacturing. O-ring securing element 214Bmay also be common and durable. In some examples, O-ring securingelement 214B may be configured to fit into a recess to help positionO-ring securing element 214B and assist to keep O-ring securing element214B in place.

FIG. 3C illustrates a side view diagram of an abrasive rotary tool thatincludes a sleeve securing element 214C securing abrasive layer 210.Sleeve securing element 214C may have a very high surface areacontacting abrasive layer 210, exterior surface 208, and shank 204, suchthat sleeve securing element 214C may secure abrasive layer 210 toabrasive assembly holder 202 and shank 204 by providing a force againstmovement of abrasive layer 210 in an axial direction away from shank204. For example, sleeve securing element 214C may couple to shank 204to keep sleeve securing element 214C in place while covering abrasivelayer 210 to secure tabs of abrasive layer 210. Sleeve securing element214C may be especially useful for curved portions of an abrasive toolwith irregular contours.

FIG. 3D illustrates a side view diagram of an abrasive rotary tool 200Dthat includes an axial securing element 214D securing abrasive layer210. Abrasive rotary tool 200D, includes an abrasive assembly holder 202and an abrasive layer 210. Abrasive layer 210 may have radial tabs thatextend radially across an end of rotary tool 200D. Abrasive assemblyholder 202 includes a three-dimensional core 206 that is adjacent to ashank 204 and includes an exterior surface 208. Axial securing element214D may be positioned at the end of rotary tool 200D in core 206 andapply an axial force into core 206. Axial securing element 214D mayinclude, for example, screw, tack, or other securing element thatsupplies an axial force against the rotary tool. For example, thesecuring element may be a screw or tack that is inserted into an end ofthe rotary tool to pinch tabs of the abrasive layer against the rotarytool. Axial securing element 214D may be recessed into rotary tool 200D,such that a whole contact surface 212 on a side or a bottom of rotarytool 200D may contact a substrate without interference from axialsecuring element 214D.

While not shown in FIGS. 3A-3D, in some examples, the securing elementmay be a clamp, a wrap, a tape, or other securing element that suppliesa force that opposes a separating force. For example, the securingelement may be a clamp that is closed based on a clamping mechanism thathas a first, unclamped state and a second, clamped state. As anotherexample, the securing element may be a tape or wrap that is wrappedaround a portion of the abrasive layer and secured by a securingmechanism, such as an adhesive or interlayer friction.

A variety of materials may be used to form the securing element. In someexamples, the securing element is at least one of an elastomer, aplastic, a tape, a metal, or any other material capable of applying asecuring force to secure the abrasive layer to the exterior surface ofthe core. For example, an elastomer or a plastic may have a highelasticity, such that the securing element may be used for a variety ofshapes and sizes of rotary tool and/or may maintain a relativelyconstant force against the abrasive layer. Elastomers that may be usedinclude, but are not limited to, polyisoprene, polybutadiene, latexrubber, silicone, polyurethane, and the like. Plastics that may be usedinclude shrink wrap plastics that may shrink when exposed to heat, forexample. As another example, a metal may have a low elasticity, suchthat the securing element may exert a force on an abrasive layer and/ormay remain rigid during abrading. Metals that may be used include, butare not limited to, aluminum, steel, and the like.

Securing elements discussed herein may have a variety of sizes. In someexamples, securing elements may be between about 0.1 cm and about 5 cmwide. In some examples, a width of the securing element may be selectedto provide an adequate adhesive force while reducing an amount ofsurface area of the contact surface covered by the securing element. Insome examples, securing elements may be between about 0.1 mm and about 1cm thick.

Securing elements discussed herein may be positioned at a variety oflocations on the abrasive layers. In some examples, the securingelements may be positioned on any portion of the abrasive layer suchthat the securing element provides a force in a radial direction towardthe rotational axis of the abrasive rotary tool, a force in an axialdirection along the rotational axis, or a combination of both. In someexamples, the securing elements may be positioned on a portion of theabrasive layer such that the securing element provides a force in axialdirection.

As explained above, an abrasive layer may be configured to fit a shapeof a three-dimensional core of an abrasive rotary tool. Correspondingly,a securing element may be configured to secure the abrasive layer to thethree-dimensional core such that the abrasive layer is secured to thecore. As such, a variety of shapes and configurations of an abrasivelayer may be used for abrasive rotary tools discussed herein. FIGS.4A-4C illustrate various configurations of abrasive layers that may beused.

FIG. 4A is a top view diagram that illustrates an abrasive layer 300that includes circumferential tabs 306. A circumferential tab may be atab that, when applied to a three-dimensional core, such asthree-dimensional core 36 of FIG. 1B, is positioned along acircumference of the three-dimensional core in an axial direction. Forexample, abrasive layer 110 of FIG. 2A may have a shape similar toabrasive layer 300 when flat. Once applied to a three-dimensional core,such as a cylindrical or bulbous core, abrasive layer 300 may havecontact surface 302 facing out from the core. A securing element maysecure abrasive layer 300 to the core at a portion 304 ofcircumferential tab 306 of abrasive layer 300.

FIG. 4B illustrates a top view diagram of an abrasive layer 310 thatincludes radial tabs 316. A radial tab may be a tab that, when appliedto a three-dimensional core, is positioned along a radius toward theaxis of rotation. Once applied to a three-dimensional core, such as acylindrical core, abrasive layer 310 may have contact surface 312 facingout from the core. A securing element may secure abrasive layer 310 tothe core at a portion 314 of radial tabs 316 of abrasive layer 310, seefor example FIG. 2C. Abrasive layer 150 of FIG. 2C may have a shapesimilar to abrasive layer 310 when flat.

FIG. 4C illustrates a top view diagram of an abrasive layer 320 thatincludes a wrapping strip. A wrapping strip may be a strip that, whenapplied to a three-dimensional core, is positioned along a circumferenceof the three-dimensional core in a spiraling direction. For example,abrasive layer 130 of FIG. 2B may have a shape similar to abrasive layer320 when flat. Once applied to a three-dimensional core, such as acylindrical core, abrasive layer 320 may have contact surface 322 facingout from the core. Two securing elements may secure abrasive layer 320to the core at a portion 324 on each end of abrasive layer 320.

Rotary tools as discussed herein may include any number of abrasivelayers. In some examples, a plurality of abrasive layers may be used ona same rotary tool. For example, a rotary tool may have a first abrasivelayer having a first set of abrasive characteristics (e.g., roughness,etc.) and a second abrasive layer having a second set of abrasivecharacteristics. One or more abrasive layers of the plurality ofabrasive layers may be secured to the rotary tool using a securingelement as discussed herein. For example, a first abrasive layer on aportion of a core proximal to a shaft may be secured by a band securingelement, while a second abrasive layer on a portion of the core distalto the shaft may be secured by an axial securing element.

Abrasive layers as discussed herein, such as abrasive layer 40, includea contact surface, such as contact surface 42, configured to contact andabrade one or more surfaces of a substrate. Abrading may includegrinding, polishing, and any other action that removes material from thesubstrate. As will be appreciated by those skilled in the art, thecontact surface can be formed according to a variety of methodsincluding, e.g., molding, extruding, embossing, and combinationsthereof.

The abrasive layer is not particularly limited and may include, but isnot limited to, traditional coated abrasives and structured abrasives(e.g. 3M TRIZACT ABRASIVE, available from 3M Company, St. Paul, Minn.).The abrasive layer may include a base layer, e.g. backing layer, and acontact layer. The base layer may be formed from a polymeric material.For example, the base layer may be formed from thermoplastics, such aspolypropylene, polyethylene, polyethylene terephthalate and the like;thermosets, such as polyurethanes, epoxy resin, and the like; or anycombinations thereof. The base layer may include any number of layers.The thickness of the base layer (i.e., the dimension of the base layerin a direction normal to the first and second major surfaces) may beless than 10 mm, less than 5 mm, less than 1 mm, less than 0.5 mm, lessthan 0.25 mm, less than 0.125 mm, or less than 0.05 mm.

In some examples, the contact surface of the abrasive layer includes amicrostructured surface. The microstructured surface may includemicrostructures configured to increase a contact pressure of the contactsurface on one or more surfaces of a substrate. In some embodiments, themicrostructured surface may include a plurality of cavities interspacedbetween the outermost abrasive material of the abrasive layer. Forexample, the shape of the cavities may be selected from among a numberof geometric shapes such as a cubic, cylindrical, prismatic,hemispherical, rectangular, pyramidal, truncated pyramidal, conical,truncated conical, cross, post-like with a bottom surface which isarcuate or flat, or combinations thereof. Alternatively, some or all ofthe cavities may have an irregular shape. In various embodiments, one ormore of the side or inner walls that form the cavities may beperpendicular relative to the top major surface or, alternatively, maybe tapered in either direction (i.e., tapered toward the bottom of thecavity or toward the top of the cavity—toward the major surface). Theangle forming the taper can range from about 1 to 75 degrees, from about2 to 50 degrees, from about 3 to 35 degrees, or from between about 5 to15 degrees. The height, or depth, of the cavities can be at least 1micron, at least 10 microns, or at least 500 microns, or at least 1 mm;less than 10 mm, less than 5 mm, or less than 1 mm. The height of thecavities may be the same, or one or more of the cavities may have aheight that is different than any number of other cavities. In someembodiments, the cavities can be provided in an arrangement in which thecavities are in aligned rows and columns. In some instances, one or morerows of cavities can be directly aligned with an adjacent row ofcavities. Alternatively, one or more rows of cavities can be offset froman adjacent row of cavities. In further embodiments, the cavities can bearranged in a spiral, helix, corkscrew, or lattice fashion. In stillfurther embodiments, the composites can be deployed in a “random” array(i.e., not in an organized pattern).

In some examples, the contact surface comprises a plurality of preciselyshaped abrasive composites. “Precisely shaped abrasive composite” refersto an abrasive composite having a molded shape that is the inverse ofthe mold cavity which is retained after the composite has been removedfrom the mold; preferably, the composite is substantially free ofabrasive particles protruding beyond the exposed surfaces of the shapebefore the abrasive layer has been used, as described in U.S. Pat. No.5,152,917 (Pieper et al.), which is incorporate herein by reference inits entirety. The plurality of precisely shaped abrasive composites mayinclude a combination of abrasive particles and resin/binder forming afixed abrasive. In some embodiments, contact surface 70 may be formed asa two-dimensional abrasive material, such as an abrasive sheet with alayer of abrasive particles held to a backing by one or more resin orother binder layers. Alternatively, the contact surface may be formed asa three-dimensional abrasive material, such as a resin or other binderlayer that contains abrasive particles dispersed therein and is formedinto a three-dimensional structure (forming a microstructured surface)via a molding or embossing process, for example, followed by curing,crosslinking, and/or crystallizing of the resin to solidify and maintainthe three-dimensional structure. The three-dimensional structure mayinclude a plurality of precisely shaped abrasive composites. In eitherembodiment, the contact surface may include an abrasive composite whichhas appropriate height to allow for the abrasive composite to wearduring use and/or dressing to expose a fresh layer of abrasiveparticles. The abrasive layer may comprise a three-dimensional,textured, flexible, fixed abrasive construction including a plurality ofprecisely shaped abrasive composites. The precisely shaped abrasivecomposites may be arranged in an array to form the three-dimensional,textured, flexible, fixed abrasive construction. The abrasive layer maycomprise abrasive constructions that are patterned. Abrasive layersavailable under the trade designation TRIZACT patterned abrasive andTRIZACT diamond tile abrasives available from 3M Company, St. Paul,Minn., are exemplary patterned abrasives. Patterned abrasive layersinclude monolithic rows of abrasive composites precisely aligned andmanufactured from a die, mold, or other techniques.

The shape of each precisely shaped abrasive composite may be selectedfor the particular application (e.g., workpiece material, workingsurface shape, contact surface shape, temperature, resin phasematerial). The shape of each precisely shaped abrasive composite may beany useful shape, e.g., cubic, cylindrical, prismatic, rightparallelepiped, pyramidal, truncated pyramidal, conical, hemispherical,truncated conical, cross, or post-like sections with a distal end.Composite pyramids may, for instance, have three, four sides, fivesides, or six sides. The cross-sectional shape of the abrasive compositeat the base may differ from the cross-sectional shape at the distal end.The transition between these shapes may be smooth and continuous or mayoccur in discrete steps. The precisely shaped abrasive composites mayalso have a mixture of different shapes. The precisely shaped abrasivecomposites may be arranged in rows, spiral, helix, or lattice fashion,or may be randomly placed. The precisely shaped abrasive composites maybe arranged in a design meant to guide fluid flow and/or facilitateswarf removal.

The precisely shaped abrasive composites may be set out in apredetermined pattern or at a predetermined location within the abrasivelayer. For example, when the abrasive layer is made by providing anabrasive/resin slurry between a backing and mold, the predeterminedpattern of the precisely shaped abrasive composites will correspond tothe pattern of the mold. The pattern is thus reproducible from abrasivelayer to abrasive layer. The predetermined patterns may be in an arrayor arrangement, by which is meant that the composites are in a designedarray such as aligned rows and columns, or alternating offset rows andcolumns. In another embodiment, the abrasive composites may be set outin a “random” array or pattern. By this is meant that the composites arenot in a regular array of rows and columns as described above. It isunderstood, however, that this “random” array is a predetermined patternin that the location of the precisely shaped abrasive composites ispredetermined and corresponds to the mold.

An abrasive material forming the contact surface of the abrasive layermay include a polymeric material, such as a resin. In some embodiments,the resin phase may include a cured or curable organic material. Themethod of curing is not critical, and may include, for instance, curingvia energy such as UV light or heat. Examples of suitable resin phasematerials include, for instance, amino resins, alkylatedurea-formaldehyde resins, melamine-formaldehyde resins, alkylatedbenzoguanamine-formaldehyde resins, acrylate resins (including acrylatesand methacrylates), phenolic resins, urethane resins, and epoxy resins.

Examples of suitable abrasive particles for the abrasive layer includecubic boron nitride, fused aluminum oxide, ceramic aluminum oxide, heattreated aluminum oxide, white fused aluminum oxide, black siliconcarbide, green silicon carbide, titanium diboride, boron carbide,silicon nitride, tungsten carbide, titanium carbide, diamond, cubicboron nitride, hexagonal boron nitride, alumina zirconia, iron oxide,ceria, garnet, fused alumina zirconia, alumina-based sol gel derivedabrasive particles and the like. The alumina abrasive particle maycontain a metal oxide modifier. The diamond and cubic boron nitrideabrasive particles may be mono crystalline or polycrystalline. Otherexamples of suitable inorganic abrasive particles include silica, ironoxide, chromia, ceria, zirconia, titania, tin oxide, gamma, alumina, andthe like. The abrasive particles may be abrasive agglomerate particles.Abrasive agglomerate particles typically comprise a plurality ofabrasive particles, a binder, and optional additives. The binder may beorganic and/or inorganic. Abrasive agglomerates may be randomly shape orhave a predetermined shape associated with them.

In some embodiments, the abrasive layer, including resin, abrasiveparticles, and any additional additives dispersed in the resin, may be acoating on the rigid support layer. In some particular embodiments, anabrasive layer may be formed from an abrasive composite layer depositedon a base layer, the base layer may include a primer layer between theabrasive composite layer and the base layer. The base layer itself maybe positioned over a backing layer with an adhesive securing the baselayer to the backing layer.

FIG. 5A-5D illustrate various configurations of three-dimensional coresthat may be used. FIG. 5A is a side view cross-sectional diagram of anabrasive rotary tool 400 that includes a securing element 414 securingan abrasive layer 410 to an abrasive assembly holder 402. Abrasiveassembly holder 402 includes a shank 404 and a three-dimensional core406. Shank 404 defines an axis of rotation for rotary tool 400.Three-dimensional core 406 is adjacent to shank 404 and includes anexterior surface 408. Abrasive layer 410 is adjacent to exterior surface408 and includes a contact surface 412 placed away from exterior surface408. Securing element 414 is positioned over at least a portion ofabrasive layer 410 to secure abrasive layer 410 to abrasive assemblyholder 402. An adhesive layer 417 is disposed between abrasive layer 410and exterior surface 408 of three-dimensional core 406.Three-dimensional core 406 includes at least one side-wall 409 adjacentto exterior surface 408 and securing element 414 secures abrasive layer410 to one side wall 409 of three-dimensional core 406. Side-wall 409may include any structure that provides a supporting surface on a sideof abrasive rotary tool 400. In the example of FIG. 5A,three-dimensional core 406 includes an inner layer 418 and an outerlayer 416. In some examples, shank 404 and at least a portion of core406, such as inner layer 418, are metal. For example, as shown in FIG.5A, shank 404 and inner layer 418 are monolithic. In some embodiments,shank 404 and inner layer 418 are not monolithic and may be composed ofdifferent materials.

FIG. 5B is a side view cross-sectional diagram of an abrasive rotarytool 420 that includes a securing element 434 securing an abrasive layer430 to an abrasive assembly holder 422. Abrasive assembly holder 422includes a shank 424 and a three-dimensional core 426. Shank 424 definesan axis of rotation for rotary tool 420. Three-dimensional core 426 isadjacent to shank 424 and includes an exterior surface 428. Abrasivelayer 430 is adjacent to exterior surface 428 and includes a contactsurface 432 placed away from exterior surface 428. Securing element 434is positioned over at least a portion of abrasive layer 430 to secureabrasive layer 430 to abrasive assembly holder 422. In the example ofFIG. 5B, three-dimensional core 426 includes a largest radial dimension,D_(c), and shank 424 includes a largest radial dimension, D_(s), suchthat the largest radial dimension, D_(c), of core 426 is greater thanthe largest radial dimension, D_(s), of shank 424.

FIG. 5C is a side view cross-sectional diagram of an abrasive rotarytool 440 that includes a securing element 454 securing an abrasive layer450 to an abrasive assembly holder 442. Abrasive assembly holder 442includes a shank 444 and a three-dimensional core 446. Shank 444 definesan axis of rotation for rotary tool 440. Three-dimensional core 446 isadjacent to shank 444 and includes an exterior surface 448. Abrasivelayer 450 is adjacent to exterior surface 448 and includes a contactsurface 452 placed away from exterior surface 448. Securing element 454is positioned over at least a portion of abrasive layer 450 to secureabrasive layer 450 to abrasive assembly holder 442. In the example ofFIG. 5C, outer layer 456 of core 446 includes a retaining channel 458,such that securing element 454 is contained in at least a portion ofretaining channel 458.

FIG. 5D is a side view cross-sectional diagram of an abrasive rotarytool 460 that includes a securing element 474 securing an abrasive layer470 to an abrasive assembly holder 462. Abrasive assembly holder 462includes a shank 464 and a three-dimensional core 466. Shank 464 definesan axis of rotation for rotary tool 460. Three-dimensional core 466 isadjacent to shank 464 and includes an exterior surface 468. Abrasivelayer 470 is adjacent to exterior surface 468 and includes a contactsurface 472 placed away from exterior surface 468. Securing element 474is positioned over at least a portion of abrasive layer 470 to secureabrasive layer 470 to abrasive assembly holder 462. In the example ofFIG. 5D, three-dimensional core 466 includes a largest radial dimension,D_(c), and shank 464 includes a largest radial dimension, D_(s). Theradial dimension, D_(c), of core 466 is less than the radial dimension,D_(s), of shank 464.

In some examples, abrasive rotary tools may include an adhesive layerbetween the exterior surface of the core and the abrasive layer. Forexample, as will be explained further in FIG. 7, an adhesive layer maybe applied to a back surface of the abrasive layer, an exterior surfaceof the core, or both, prior to coupling the abrasive layer to theexterior surface. In some examples, the adhesive layer includes apressure sensitive adhesive.

The three-dimensional core of the abrasive rotary tools discussed hereinmay have a variety of shapes. In some examples, the shape of thethree-dimensional core may be at least one of: cylindrical, bulbous,conical, cup-shaped, and the like. The three-dimensional core of theabrasive rotary tools discussed herein may be formed from a variety ofmaterials. In some examples, the three-dimensional core includes atleast one of a metal, such as aluminum 6061, 2011, or 2024 or steel4140, W1, or 01; a plastic, such as nylon, polycarbonate, or acrylic; anelastomer, such as nitriles, fluoroelastomers, chloroprenes,epichlorohydrins, silicones, urethanes, polyacrylates, EPDM (ethylenepropylene diene monomer) rubbers, SBR (styrene butadiene rubber), butylrubbers; and the like. In some embodiments, the three-dimensional coremay include a foam, e.g. a foam rubber.

In some examples, the three-dimensional core may include more than onelayer. For example, the three-dimensional core may include a metal andan elastomer or a plastic and an elastomer. In some examples, such asFIGS. 5A and 5C, the inner layer and the outer layer of the coreincludes a rigid layer and an elastic layer, respectively, such that theelastic layer includes the exterior surface of the core. The rigid layermay be configured to provide support to the abrasive layer duringabrasion against the surface of the substrate to be abraded by theabrasive rotary tool, such that the contact surface remainssubstantially planar. For example, the rigid layer may include materialsthat have a high hardness and/or high elastic modulus. The elastic layermay be configured to compress during abrasion of the substrate, suchthat the contact surface may have more consistent contact with thesubstrate. For example, the elastic layer may include materials thathave a low hardness and/or low elastic modulus. In some embodiments, thetensile modulus of the rigid layer is greater than the tensile modulusof the elastic layer. For example, the tensile modulus of the rigidlayer may be 2 times, 5 time 10 times 50 times or even 100 time greaterthan the tensile modulus of the elastic layer.

In some embodiments, the rigid layer and the elastic layer, or any otherlayer of the three-dimensional core, may each be composed of a materialselected according to softness. Softness of a material may be correlatedwith the conformability of the material; generally, a softer materialmay have a higher conformability at a given contact pressure. Softnessmay be represented by and selected based on a variety of properties ofeach material of the rigid support layer and the elastic layer. Forexample, a softer material may be a material with a lower hardness (asindicated using any appropriate hardness scale, such as Shore A or ShoreOO), a material with a lower elastic modulus, a material with a highercompressibility (typically quantified via a material's Poisson's ratioor deflection), or a material with a modified structure, such ascontaining a plurality of gas inclusions such as a foam, etc.

In some embodiments, the rigid layer and the elastic layer may each becomposed of a material selected according to hardness. Hardness mayrepresent a measure of each of the rigid support layer and the elasticlayer to deform in response to a force. In some cases, the hardness maybe most appropriately measured using different scales for the rigidsupport layer and the elastic layer (e.g., Shore A durometer for theelastic layer and Rockwell scale for the rigid support layer). In someexamples, the elastic layer has a Shore A hardness of less than 80. Insome examples, the three-dimensional core, such as an elastic layer, arigid layer, or both, has a Shore A hardness of greater than 25. In someembodiments, at least one of the Shore A, Shore D and Shore OO hardnessof the rigid layer is greater than the corresponding Shore A, Shore D orShore OO hardness of the elastic layer.

In some examples, the three-dimensional core includes a rigid layer thatincludes at least one of a metal layer and plastic layer adjacent theelastic layer. In some examples, at least a portion of thethree-dimensional core and shank are a unitary body. In some examples,the elastic layer comprises at least one of an elastomer, a foam, afabric, or a nonwoven material. Suitable elastomers may includethermoset elastomers such as, for example, nitriles, fluoroelastomers,chloroprenes, epichlorohydrins, silicones, urethanes, polyacrylates,EPDM (ethylene propylene diene monomer) rubbers, SBR (styrene butadienerubber), butyl rubbers, etc.

In various embodiments, abrasive rotary tools as described herein may besuitable for edge or major surface grinding a cover glass. For example,a cover glass may include various surfaces for which a high pressure ona small surface area may create a high peel force on an abrasive layerof an abrasive rotary tool. FIG. 6 illustrates a cover glass for anelectronic device such as a cellular phone, personal music player, orother electronic device. In some embodiments, cover glass 500 may be acomponent of a touchscreen for the electronic device. Cover glass 500may be an alumina-silicate based glass with a thickness of less than 1mm, although other compositions are also possible, such as a thicknessof less than 5 mm, less than 4 mm, less than 3 mm or even less than 2mm.

Cover glass 500 includes a first major surface 502 opposing a secondmajor surface 504. Generally, but not always, major surfaces 502, 504are planar surfaces. Edge surface 506 follows the perimeter of majorsurfaces 502, 504, the perimeter including rounded corners 508. Edgesurface 506 intersects first major surface 502 at a first corner andsecond major surface 504 at a second corner, the first and secondcorners, generally, extends around the entire perimeter of thesubstrate.

To provide an increased resistance to cracking and improved appearance,the surfaces of cover glass 500, including major surfaces 502, 504 andedge surface 506 should be smoothed to the extent practical duringmanufacturing of cover glass 500. In addition, as disclosed herein,abrasive rotary tools may be used to reduce edge surface roughness, suchas edge surface 506 and corners 508 using a CNC machine prior. Anabrasive rotary tool with enhanced adhesion of an abrasive layer maymore consistently abrade edge surface 506 and corners 508, as a contactsurface of the abrasive layer may remain intact as abrasive layerremains coupled to the abrasive rotary tool.

FIG. 7 is a flowchart illustrating example techniques for manufacturingan abrasive rotary tool that includes a securing element securing anabrasive layer to an abrasive assembly holder. While the techniques ofFIG. 7 will be described with reference to abrasive rotary tool 18 ofFIG. 1B, other components and abrasive rotary tools may be used.

In some examples, the method includes cutting an abrasive material toform an abrasive layer, such as abrasive layer 40 (600). For example, arotary die cutting machine may cut a sheet of an abrasive material toform abrasive layer 40. The die may be configured to cut abrasive layer40 such that abrasive layer 40 forms a desire contact surface, such ascontact surface 42, after coupling of abrasive layer 40 to athree-dimensional core, such as three-dimensional core 36.

In some examples, the method includes applying an adhesive to at leastone of exterior surface 38 and abrasive layer 40 before positioningabrasive layer 40 on exterior surface 38. For example, an adhesive layermay be applied to one or both of exterior surface 38 and/or a backingsurface, opposite contact surface 42, of abrasive layer 40 to secureadhesive layer 40 to exterior surface 38 using an adhesive force of theadhesive layer. In some examples, the adhesive force of the adhesivelayer is less than a total securing force required for securing abrasivelayer 40 to abrasive rotary tool 18 for a desired period of operation.In some examples, abrasive layer 40 may already include an adhesive,such as an adhesive backing.

The method includes positioning abrasive layer 40 adjacent to exteriorsurface 38 of three-dimensional core 36 of abrasive assembly holder 32(610). For example, the backing surface of abrasive layer 40 maysubstantially contact exterior surface 38 of core 36, such as greaterthan 90% of the backing surface contacting exterior surface 38.

The method includes positioning at least one securing element 44 over aportion of abrasive layer 40, securing abrasive layer 40 to abrasiveassembly holder 32 (620). For example, securing element 44 may beplaced, clasped, shrank, cured, heated, or received any other actionthat positions securing element 44 on abrasive layer 40, such thatabrasive layer 40 is secured to abrasive assembly holder 32.

FIG. 8 is a flowchart illustrating example techniques for abrading asubstrate using an abrasive rotary tool. While the techniques of FIG. 8will be described with reference to an operator manipulating assembly 10of FIG. 1A, other assemblies and agents of operation may be used. Theoperator provides computer-controlled machining system 12, whichincludes computer controlled rotary tool holder 20 and substrateplatform 22 (700). The operator secures an abrasive rotary tool torotary tool holder 20 of computer-controlled machining system 12 (710).As described herein, the abrasive rotary tool includes at least onesecuring element positioned over a portion of an abrasive layer tosecure the abrasive layer to the abrasive assembly holder of theabrasive rotary tool. The operator operates computer-controlledmachining system 12, such as through controller 14, to abrade one ormore surfaces of a substrate (720), such as substrate 16 of FIG. 1A,with the abrasive rotary tool. The operator may continue abrading withthe abrasive rotary tool until the abrasive rotary tool requiresreplacement. For abrasive rotary tools discussed herein that include asecuring element to secure an abrasive layer to the rotary tool, theperiod for replacement of the abrasive rotary tool may be greater thanabrasive rotary tools that do not include a securing element to securean abrasive layer.

Select embodiments of the present disclosure include, but are notlimited to, the following:

In a first embodiment, the present disclosure provides an abrasiverotary tool, comprising:

an abrasive assembly holder including:

-   -   a shank defining an axis of rotation for the rotary tool; and    -   a three-dimensional core, having an exterior surface, wherein        the three-dimensional core is adjacent to the shank;

an abrasive layer adjacent to the exterior surface, wherein the abrasivelayer includes a contact surface; and

at least one securing element positioned over a portion of the abrasivelayer, securing the abrasive layer to the abrasive assembly holder.

In a second embodiment, the present disclosure provides an abrasiverotary tool according to the first embodiment, wherein thethree-dimensional core includes at least one side-wall adjacent to theexterior surface and the securing element secures the abrasive layer tothe at least one side wall of the three-dimensional core.

In a third embodiment, the present disclosure provides an abrasiverotary tool according to the first or second embodiment, wherein atleast a portion of the abrasive layer includes tabs.

In a fourth embodiment, the present disclosure provides an abrasiverotary tool according to the third embodiment, wherein the securingelement is positioned over at least a portion of the tabs.

In a fifth embodiment, the present disclosure provides an abrasiverotary tool according to the fourth embodiment, wherein the securingelement is only positioned over at least a portion of the tabs.

In a sixth embodiment, the present disclosure provides an abrasiverotary tool according to any one of the first through fifth embodiments,wherein the abrasive layer is secured to the three-dimensional corewithout overlap of the abrasive layer.

In a seventh embodiment, the present disclosure provides an abrasiverotary tool according to any one of the first through sixth embodiments,wherein the contact surface of the abrasive layer includes amicrostructured surface.

In an eighth embodiment, the present disclosure provides an abrasiverotary tool according to any one of the first through seventhembodiments, wherein the contact surface comprises a plurality ofprecisely shaped abrasive composites.

In a ninth embodiment, the present disclosure provides an abrasiverotary tool according to any one of the first through eighthembodiments, wherein at least a portion of the three-dimensional coreand shank are a unitary body.

In a tenth embodiment, the present disclosure provides an abrasiverotary tool according to any one of the first through ninth embodiments,wherein the securing element is at least one of an elastomer, a plastic,a tape, and a metal.

In an eleventh embodiment, the present disclosure provides an abrasiverotary tool according to the tenth embodiment, wherein the elastomer isat least one of an O-ring, a band, a wrap, a thermally shrinkablesleeve, and a flange.

In a twelfth embodiment, the present disclosure provides an abrasiverotary tool according to the tenth embodiment, wherein the plastic is atleast one of an O-ring, a band, a wrap, a thermally shrinkable sleeve,and a flange.

In a thirteenth embodiment, the present disclosure provides an abrasiverotary tool according to the tenth embodiment, wherein the securingelement is only positioned over at least a portion of the tabs.

In a fourteenth embodiment, the present disclosure provides an abrasiverotary tool according to any one of the first through thirteenthembodiments, wherein the three-dimensional core includes at least one ofa metal, elastomer, and a plastic.

In a fifteenth embodiment, the present disclosure provides an abrasiverotary tool according to any one of the first through fourteenthembodiments, wherein the three-dimensional core includes a metal and anelastomer or a plastic and an elastomer.

In a sixteenth embodiment, the present disclosure provides an abrasiverotary tool according to any one of the first through fifteenthembodiments, wherein the three-dimensional core includes an elasticlayer which includes the exterior surface.

In a seventeenth embodiment, the present disclosure provides an abrasiverotary tool according to the sixteenth embodiment, wherein thethree-dimensional core includes at least one of a metal layer andplastic layer adjacent the elastic layer.

In an eighteenth embodiment, the present disclosure provides an abrasiverotary tool according to the sixteenth or seventeenth embodiment,wherein the elastic layer has a Shore A hardness of less than 80.

In a nineteenth embodiment, the present disclosure provides an abrasiverotary tool according to any one of the sixteenth through eighteenthembodiments, wherein the elastic layer comprises at least one of anelastomer, a foam, a fabric, or a nonwoven material.

In a twentieth embodiment, the present disclosure provides an abrasiverotary tool according to any one of the first through nineteenthembodiments, wherein the three-dimensional core has a Shore A hardnessof greater than 25.

In a twenty-first embodiment, the present disclosure provides anabrasive rotary tool according to any one of the first through twentiethembodiments, wherein the three-dimensional core includes a largestradial dimension and the shank includes a largest radial dimension andwherein the largest radial dimension of the core is greater than thelargest radial dimension of the shank.

In a twenty-second embodiment, the present disclosure provides anabrasive rotary tool according to any one of the first through twentiethembodiments, wherein the three-dimensional core includes a largestradial dimension and the shank includes a largest radial dimension andwherein the radial dimension of the core is less than or equal to theradial dimension of the shank.

In a twenty-third embodiment, the present disclosure provides anabrasive rotary tool according to any one of the first throughtwenty-second embodiments, wherein the shank and at least a portion ofthe core are metal.

In a twenty-fourth embodiment, the present disclosure provides anabrasive rotary tool according to any one of the first throughtwenty-third embodiments, further comprising an adhesive layer disposedbetween the abrasive layer and the exterior surface of the core.

In a twenty-fifth embodiment, the present disclosure provides anabrasive rotary tool according to the twenty-fourth embodiment, whereinthe adhesive layer includes a pressure sensitive adhesive.

In a twenty-sixth embodiment, the present disclosure provides anabrasive rotary tool according to any one of the first throughtwenty-fifth embodiments, wherein the core includes a retaining channel.

In a twenty-seventh embodiment, the present disclosure provides anabrasive rotary tool according to the twenty-sixth embodiment, whereinthe securing element is contained in at least a portion of the retainingchannel.

In a twenty-eighth embodiment, the present disclosure provides anassembly, comprising:

a computer-controlled machining system comprising a computer controlledrotary tool holder and a substrate platform;

a substrate secured to the substrate platform; and

an abrasive rotary tool of any of the first through twenty-seventhembodiments.

In a twenty-ninth embodiment, the present disclosure provides anassembly according to the twenty-eighth embodiment, wherein thesubstrate is a component for an electronic device.

In a thirtieth embodiment, the present disclosure provides an assemblyaccording to the twenty-ninth embodiment, wherein the component for anelectronic device is a transparent, display element.

In a thirty-first embodiment, the present disclosure provides a methodfor polishing a substrate, comprising:

providing a computer-controlled machining system including a computercontrolled rotary tool holder and a substrate platform;

securing an abrasive rotary tool to the rotary tool holder of thecomputer-controlled machining system, wherein the abrasive rotary toolcomprises:

-   -   an abrasive assembly holder including:        -   a shank defining an axis of rotation for the rotary tool;            and        -   a three-dimensional core, having an exterior surface,            wherein the three-dimensional core is adjacent to the shank;    -   an abrasive layer adjacent to the exterior surface, wherein the        abrasive layer includes a contact surface; and    -   at least one securing element positioned over a portion of the        abrasive layer, securing the abrasive layer to the abrasive        assembly holder;

operating the computer-controlled machining system to abrade a contactsurface of the substrate using the abrasive layer of the abrasive rotarytool.

In a thirty-second embodiment, the present disclosure provides a methodaccording to the thirty-first embodiment, further comprising:

positioning an abrasive layer adjacent to an exterior surface of athree-dimensional core of an abrasive assembly holder, wherein thethree-dimensional core is adjacent to a shank of the abrasive assemblyholder, wherein the abrasive layer includes a contact surface, whereinthe shank defines an axis of rotation of the rotary tool; and

positioning at least one securing element over a portion of the abrasivelayer, securing the abrasive layer to the abrasive assembly holder.

In a thirty-third embodiment, the present disclosure provides anassembly according to the thirty-second embodiment, further comprisingapplying an adhesive to at least one of the exterior surface and theabrasive layer before positioning the abrasive layer.

EXAMPLES

The operation of the present disclosure will be further described withregard to the following detailed examples. These examples are offered tofurther illustrate the various specific and preferred embodiments andtechniques. It should be understood, however, that many variations andmodifications may be made while remaining within the scope of thepresent disclosure.

FIGS. 9A-H are diagrams of various configurations of rotary tools asdisclosed herein.

FIG. 9A is a perspective view diagram of an abrasive rotary tool 820which included a sleeve securing element 834 that secured an abrasivelayer 830, that includes tabs, to an abrasive assembly holder 822, whileFIG. 9B is another perspective view diagram of abrasive rotary tool 820of FIG. 9A. Abrasive assembly holder 822 included a shank 824 and athree-dimensional core 826. Shank 824 defined an axis of rotation forrotary tool 820 and was manufactured with 6061 type aluminum.Three-dimensional core 826 was adjacent to shank 824 and included anexterior surface 828, and was manufactured with 6061 type aluminum. Inthe examples of FIGS. 9A and 9B, three-dimensional core 826 had abulbous shape. Abrasive layer 830 was adjacent to exterior surface 828and included a contact surface 832. Abrasive layer 830 was die cut from578XA-TP2 with PSA (available from 3M Company, St. Paul, Minn.). Sleevesecuring element 834 was positioned over the tabs of abrasive layer 830and heated to cause shrinkage thereof, thereby securing the tabs ofabrasive layer 830 to abrasive assembly holder 822. Sleeve securingelement 814 was a heat shrink tubing purchased from McMaster-Carr, P.O.Box 4355, Chicago, Ill.

FIG. 9C is a perspective view diagram of an abrasive rotary tool 840which included an O-ring securing element 854 that secured an abrasivelayer 850, that includes tabs, to an abrasive assembly holder 842, whileFIG. 9D is another perspective view diagram of abrasive rotary tool 840of FIG. 9C. Abrasive assembly holder 842 included a shank 844 and athree-dimensional core 846. Shank 844 defined an axis of rotation forrotary tool 840 and was manufactured with 6061 type aluminum.Three-dimensional core 846 was adjacent to shank 844 and included anexterior surface 848, and was manufactured with 6061 type aluminum. Inthe examples of FIGS. 9C and 9D, three-dimensional core 846 had acylindrical shape. Abrasive layer 850 was adjacent to exterior surface848 and included a contact surface 852. Abrasive layer 850 was die cutfrom 578XA-TP2 with PSA (available from 3M Company, St. Paul, Minn.).O-ring securing element 854 was positioned over the tabs of abrasivelayer 850 to secure the tabs of abrasive layer 850 to abrasive assemblyholder 842. O-ring securing element 854 was Buna -N material purchasedfrom McMaster-Carr, PO Box 4355, Chicago, Ill.

FIG. 9E is a perspective view diagram of an abrasive rotary tool 860which included an axial securing element 874 securing an abrasive layer870, that included tabs, to an abrasive assembly holder 862, while FIG.9F is another perspective view diagram of abrasive rotary tool 860 ofFIG. 9E. Abrasive assembly holder 862 included a shank 864 and athree-dimensional core 866. Shank 864 defined an axis of rotation forrotary tool 860 and was manufactured with 6061 type aluminum.Three-dimensional core 866 was adjacent to shank 864 and included anexterior surface 868, and was manufactured with 6061 type aluminum. Inthe examples of FIGS. 9E and 9F, three-dimensional core 866 had acylindrical shape. Abrasive layer 870 was adjacent to exterior surface868 and included a contact surface 872. Abrasive layer 870 was die cutfrom 578XA-TP2 with PSA (available from 3M Company, St. Paul, Minn.).Axial securing element 874 was positioned over the tabs of abrasivelayer 870 to secure the tabs of abrasive layer 870 to abrasive assemblyholder 862. Axial securing element 874 was a common threaded screw witha tapered head.

FIG. 9G is a perspective view diagram of an abrasive rotary tool 880that included two band securing elements 894A and 894B securing awrapped abrasive layer 890, that included tabs, to an abrasive assemblyholder 882, while FIG. 9H is another perspective view diagram ofabrasive rotary tool 880 of FIG. 9G. Abrasive assembly holder 882included a shank 884 and a three-dimensional core 886. Shank 884 definedan axis of rotation for rotary tool 880 and was manufactured with 6061type aluminum. Three-dimensional core 886 was adjacent to shank 884 andincluded an exterior surface 888, and was manufactured with 6061 typealuminum. In the examples of FIGS. 9G and 9H, three-dimensional core 886had a cylindrical shape. Abrasive layer 890 was adjacent to exteriorsurface 888 and included a contact surface 892. Abrasive layer 890 wasdie cut from 578XA-TP2 with PSA (available from 3M Company, St. Paul,Minn.). Band securing elements 894A and 894B were each positioned overthe strips of abrasive layer 890 and heated to cause shrinkage thereof,thereby securing the strips of abrasive layer 890 to abrasive assemblyholder 882. Band securing elements 894A and 894B were heat shrink tubingpurchased from McMaster-Carr, PO Box 4355, Chicago, Ill.

Various embodiments of the invention have been described. These andother embodiments are within the scope of the following claims.

1. An abrasive rotary tool, comprising: an abrasive assembly holderincluding: a shank defining an axis of rotation for the rotary tool; anda three-dimensional core, having an exterior surface, wherein thethree-dimensional core is adjacent to the shank; an abrasive layeradjacent to the exterior surface, wherein the abrasive layer includes acontact surface; and at least one securing element positioned over aportion of the abrasive layer, securing the abrasive layer to theabrasive assembly holder.
 2. The abrasive rotary tool of claim 1,wherein the three-dimensional core includes at least one side-walladjacent to the exterior surface and the securing element secures theabrasive layer to the at least one side wall of the three-dimensionalcore.
 3. The abrasive rotary tool of claim 1, wherein at least a portionof the abrasive layer includes tabs.
 4. The abrasive rotary tool ofclaim 3, wherein the securing element is positioned over at least aportion of the tabs.
 5. The abrasive rotary tool of claim 4, wherein thesecuring element is only positioned over at least a portion of the tabs.6. The abrasive rotary tool of claim 1, wherein the abrasive layer issecured to the three-dimensional core without overlap of the abrasivelayer.
 7. (canceled)
 8. The abrasive rotary tool of claim 1, wherein thecontact surface of the abrasive layer comprises a plurality of preciselyshaped abrasive composites.
 9. The abrasive rotary tool of claim 1,wherein at least a portion of the three-dimensional core and shank are aunitary body.
 10. The abrasive rotary tool of claim 1, wherein thesecuring element is at least one of an elastomer, a plastic, a tape, anda metal.
 11. The abrasive rotary tool of claim 10, wherein the elastomeris at least one of an O-ring, a band, a wrap, a thermally shrinkablesleeve, a screw, and a flange.
 12. The abrasive rotary tool of claim 10,wherein the plastic is at least one of an O-ring, a band, a wrap, athermally shrinkable sleeve, a screw, and a flange.
 13. The abrasiverotary tool of claim 10, wherein the metal is at least one of an O-ring,a band, a wrap, and a flange.
 14. The abrasive rotary tool of claim 1,wherein the three-dimensional core includes at least one of a metal,elastomer, and a plastic.
 15. (canceled)
 16. The abrasive rotary tool ofclaim 1, wherein the three-dimensional core includes an elastic layerwhich includes the exterior surface.
 17. (canceled)
 18. The abrasiverotary tool of claim 16, wherein the elastic layer has a Shore Ahardness of less than
 80. 19-25. (canceled)
 26. The abrasive rotary toolof claim 1, wherein the core includes a retaining channel.
 27. Theabrasive rotary tool of claim 26, wherein the securing element iscontained in at least a portion of the retaining channel.
 28. Anassembly, comprising: a computer-controlled machining system comprisinga computer controlled rotary tool holder and a substrate platform; asubstrate secured to the substrate platform; and an abrasive rotary toolcomprising: an abrasive assembly holder including: a shank defining anaxis of rotation for the rotary tool; and a three-dimensional core,having an exterior surface, wherein the three-dimensional core isadjacent to the shank; an abrasive layer adjacent to the exteriorsurface, wherein the abrasive layer includes a contact surface; and atleast one securing element positioned over a portion of the abrasivelayer, securing the abrasive layer to the abrasive assembly holder.29-30. (canceled)
 31. A method for polishing a substrate, comprising:providing a computer-controlled machining system including a computercontrolled rotary tool holder and a substrate platform; securing anabrasive rotary tool to the rotary tool holder of thecomputer-controlled machining system, wherein the abrasive rotary toolcomprises: an abrasive assembly holder including: a shank defining anaxis of rotation for the rotary tool; and a three-dimensional core,having an exterior surface, wherein the three-dimensional core isadjacent to the shank; an abrasive layer adjacent to the exteriorsurface, wherein the abrasive layer includes a contact surface; and atleast one securing element positioned over a portion of the abrasivelayer, securing the abrasive layer to the abrasive assembly holder;operating the computer-controlled machining system to abrade a contactsurface of the substrate using the abrasive layer of the abrasive rotarytool.
 32. A method for manufacturing an abrasive rotary tool,comprising: positioning an abrasive layer adjacent to an exteriorsurface of a three-dimensional core of an abrasive assembly holder,wherein the three-dimensional core is adjacent to a shank of theabrasive assembly holder, wherein the abrasive layer includes a contactsurface, wherein the shank defines an axis of rotation of the rotarytool; and positioning at least one securing element over a portion ofthe abrasive layer, securing the abrasive layer to the abrasive assemblyholder.
 33. (canceled)